Research in this laboratory centers on the processes of morphogenesis and cytodifferentiation during embryonic development. During the coming grant year, we will concentrate on quantitation of actin, myosin, and tubulin during embryonic organ formation. These molecules play critical roles in morphogenetic movements of epithelia during specific stages of organogenesis. However, it is not known if quantitative changes in their concentrations occurs during these morphogenetic events. We have developed quantitative radioimmunoassays for each of these proteins, and will analyze their concentrations at successive morphogenetic steps in lens formation, neurulation, and lung and salivary gland branching development. In addition, we will examine the role of calcium ion in regulating branch point formation in developing lung and salivary epithelia. Finally, we will assess the roles and molecular species of collagen involved in branching morphogenesis. BIBLIOGRAPHIC REFERENCES: B. S. Spooner and G. W. Conrad. 1975. The role of extracellular materials in cell movement. I. Inhibition of mucopolysaccharide synthesis does not stop ruffling membrane activity or cell movement. J. Cell Biol. 65: 286-297. B. S. Spooner. 1975. Microfilaments, microtubules and extracellular materials in morphogenesis. BioScience 25: 440-451.